Utricularia aff minutissima is a terrestrial bladderwort found in tropical regions of Australia. This post describes the diminutive relative of U. minutissima, which might possibly be distinct from the larger form found across SE Asia.
The plants I saw around Darwin and Far North Queensland produce flowers around 2 mm in length. The species produces pink to purple blooms, The lower corolla lip is domed, and shallowly divided into three lobes at its extremity. The spur is longer than the lower corolla lip and thrust forwards at a horizontal axis, typically curving upwards at the end. The upper corolla lip is small. The peduncle is glabrous.
I observed U. aff. minutissima growing in wet sandy substrates in seepages within the seasonally inundated floodplains near Darwin. The species was common although its diminuitive size meant that it was often overlooked. Although many flower buds were seen, the open flowers were rare (perhaps due to bad luck).
U. aff. minutissima is recognisable by its domed flowers. The small form I observed can be distinguished from other domed species by its size alone, but unopened flower buds could be mistaken at a glance for U. simmonsii, which occurs at a similar size scale. Careful examination is enough to distinguish it.